bzip2: extend/fix the Host/Install rule to install libbz2.so files

bzip2: extend/fix the Host/Install rule to install libbz2.so files

It looks like the bzip2 package does not install any shared libs
and has no build rules to install any shared libs.

So, for the host build we're installing the libbz2 shared libs manually
so that other modules can link against them.

Signed-off-by: Alexandru Ardelean <ardeleanalex@gmail.com>
Backport of r47245

git-svn-id: svn://svn.openwrt.org/openwrt/branches/chaos_calmer@47269 3c298f89-4303-0410-b956-a3cf2f4a3e73